Backlight module and display device

ABSTRACT

A backlight module and a display device are provided. The backlight module includes a light source structure and at least one optical film. The optical film is disposed above the light source structure. The optical film includes a main body and plural optical structures. The optical structures are disposed on the main body. Each of the optical structures is a tapered structure. Each of the optical structures has plural side surfaces, and a portion of light emitted from the light source structure is guided toward plural primary directions when passing through the side surfaces of the optical structures, and therefore the light emitted from the light source is no longer concentrated on the top of each of the optical structures.

RELATED APPLICATIONS

This application is a continuation application of InternationalApplication No. PCT/CN2019/086763 filed on May 14, 2019, which isincorporated herein by reference.

BACKGROUND Field of Invention

The present disclosure relates to a light source element. Moreparticularly, the present disclosure relates to a light source structureand its applications to a backlight module and a display device.

Description of Related Art

A direct-light-type backlight module includes a back plate, plurallight-emitting diodes and an optical film. The light-emitting diodes arearrayed on the back plate. The optical film is disposed above thelight-emitting diodes to mix light generated by the light-emittingdiodes.

Referring to FIG. 1 to FIG. 3, FIG. 1 is a schematic structural diagramshowing a conventional light-emitting diode 100, FIG. 2 is a diagram ofray tracing simulation of the conventional light-emitting diode 100, andFIG. 3 is a diagram of light-mixing effect simulation of theconventional light-emitting diode 100. In the conventionallight-emitting diode 100, a light-emitting chip 110 is packaged in themiddle of a package body 120 to form a light-emitting body 110 a, andthe light-emitting body 110 a is disposed on a circuit board 130.Therefore, light generated by the light-emitting chip 110 is mainlyemitted from the top of the package body 120, so that the light emittedfrom the top of the package body 120 has high intensity and the lightemitted from both sides of the package body is weak, thus resulting indark areas formed between two adjacent light-emitting bodies 110 a. Thedark area formed between any two adjacent light-emitting bodies 110 alocated along an oblique direction is the most obvious (i.e. the darkarea R1 as shown in FIG. 3), thus resulting in obvious contrastingappearance caused by the bright and dark areas of the backlight moduleand uneven light mixing phenomenon.

SUMMARY

One object of the present disclosure is to provide a light sourcestructure, a backlight module and a display device, in which the lightsource structure can generate uniformly mixed light to enhance theoptical appearance.

According to the aforementioned object, a light source structure isprovided. The light source structure includes a substrate, plurallight-emitting units, and plural packaging structures. Thelight-emitting units are arrayed on the substrate, in which each of thelight-emitting units has a central optical axis which is vertical to thesubstrate. The packaging structures respectively cover and correspond tothe light-emitting units, in which each of the packaging structures hasa central axis which is vertical to the substrate. The central opticalaxes of the light-emitting units are shifted in the same direction fromthe central axes of the packaging structures.

According to an embodiment of the present invention, the light-emittingunits are arrayed in a first direction and a second direction. Anincluded angle is formed between a connecting line and the firstdirection or the second direction, wherein the connecting line islocated between the central optical axis of each of the light-emittingunits and the central axis of the packaging structure corresponding tothe each of light-emitting units.

According to an embodiment of the present invention, the included angleis 45 degrees.

According to an embodiment of the present invention, a first distance isformed between the central optical axes of any two adjacentlight-emitting units. A second distance is formed between the centralaxes of any two adjacent packaging structures. The first distance isequal to the second distance.

According to an embodiment of the present invention, an offset distanceis formed between the central optical axis of each of the light-emittingunits and the central axis of the packaging structure corresponding tothe each of the light-emitting units, and the offset distances areequal.

According to the aforementioned object, a backlight module is provided.The backlight module includes the aforementioned light source structureand at least one optical film. The optical film is disposed above thelight source structure. The optical film includes a main body and pluraloptical structures. The optical structures are disposed on the mainbody. Each of the optical structures is a tapered structure.

According to an embodiment of the present invention, each of the opticalstructures faces towards the light source structure.

According to an embodiment of the present invention, the main body has afirst optical surface and a second optical surface opposite to eachother. Each of the optical structures has a vertex and a central line,in which the central line is vertical to the first optical surface orthe second optical surface of the main body, and the vertex is locatedon the central line.

According to an embodiment of the present invention, each of the opticalstructures has a plurality of side surfaces, and each of the sidesurfaces is a single surface. Each of the side surfaces has a normalline, and extending directions of the normal lines are different.Included angles between each of the normal lines and each of the centrallines are equal.

According to an embodiment of the present invention, each of the opticalstructures has a plurality of side surfaces, and each of the sidesurfaces is a composite surface which is constituted by two or more thantwo surface units jointed in an extending direction of the central line.

According to an embodiment of the present invention, each of the opticalstructures has plural side surfaces surrounding the central line, andeach of the side surfaces is a composite surface which is constituted bytwo or more layers of surface units jointed in an extending direction ofthe central line. Each of the surface units has a normal line. Pluralincluded angles are formed between the central line and the normal linesof the surface units. The included angles between the central line andthe normal lines of the surface units which are located in the samelayer and surround the central line are substantially the same. Theincluded angles between the central line and the normal lines of thesurface units which are located in different layers and surround thecentral line are different.

According to an embodiment of the present invention, the included anglesbetween the central line and the normal lines of the surface units whichare located near to the vertex are smaller than the included anglesbetween the central line and the normal lines of the surface units whichare located away from the vertex.

According to an embodiment of the present invention, the included anglesbecome smaller with increased distances between the respective surfaceunits and the first optical surface.

According to an embodiment of the present invention, the main body has afirst optical surface and a second optical surface opposite to eachother. Each of the optical structures is a convex structure protrudingfrom the first optical surface and/or the second optical surface.

According to an embodiment of the present invention, the main body has afirst optical surface and a second optical surface opposite to eachother. Each of the optical structures is a concave structure which isrecessed into the first optical surface and/or the second opticalsurface.

According to the aforementioned object, a display device is provided.The display device includes the aforementioned backlight module and adisplay panel. The display panel is disposed in front of the backlightmodule.

According to the aforementioned embodiments of the present disclosure,by shifting the light-emitting units relative to the packagingstructures, the amount of the light emitted from the side surfaces ofthe packaging structures can be increased, thereby increasing thebrightness of the dark areas between any two adjacent packagingstructures and reducing the contrast between the bright and dark areasof the light source structure, so as to achieve a good light mixingeffect. On the other hand, the optical film of the present disclosurewhich has special optical structures can be cooperated with the lightsource structure of the present disclosure, so that light can bediverted to travel along different directions when passing through theoptical structures, thereby achieving the objects of uniformizing lightand improving the light luminance.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the followingdetailed description of the embodiment, with reference made to theaccompanying drawings as follows:

FIG. 1 is a schematic structural diagram showing a conventionallight-emitting diode;

FIG. 2 is a diagram of ray tracing simulation of the conventionallight-emitting diode;

FIG. 3 is a diagram of light-mixing effect simulation of theconventional light-emitting diode;

FIG. 4 is a schematic diagram showing a light source structure inaccordance with an embodiment of the present disclosure;

FIG. 5 is a partial side view showing the light source structure inaccordance with an embodiment of the present disclosure;

FIG. 6 is a diagram of ray tracing simulation of the light sourcestructure in accordance with an embodiment of the present disclosure;

FIG. 7A is a schematic diagram showing a light source structure inaccordance with an embodiment of the present disclosure;

FIG. 7B is a diagram of light-mixing effect simulation of the lightsource structure in accordance with an embodiment of the presentdisclosure;

FIG. 8 is a schematic diagram showing a display device in accordancewith an embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram showing an optical structure inaccordance with an embodiment of the present disclosure;

FIG. 10 is a schematic structural diagram showing another opticalstructure in accordance with an embodiment of the present disclosure;

FIG. 11 is a schematic structural diagram showing another opticalstructure in accordance with an embodiment of the present disclosure;

FIG. 12 is a schematic structural diagram showing an optical film inaccordance with another embodiment of the present disclosure;

FIG. 13 is a diagram of light-mixing effect simulation of the opticalstructure shown in FIG. 10; and

FIG. 14 is a diagram of light-mixing effect simulation of the opticalstructure shown in FIG. 9; and

FIG. 15 is a schematic diagram showing a display device in accordancewith an embodiment of the present disclosure.

DETAILED DESCRIPTION

Simultaneously referring to FIG. 4 and FIG. 5, FIG. 4 is a schematicdiagram showing a light source structure 300 in accordance with anembodiment of the present disclosure, and FIG. 5 is a partial side viewshowing the light source structure 300 in accordance with an embodimentof the present disclosure. The light source structure 300 mainlyincludes a substrate 310, plural light-emitting units 320 and pluralpackaging structures 330. The light-emitting units 320 are arrayed onthe substrate 310, and each of the light-emitting units 320 has acentral optical axis S1 vertical to the substrate 310. In the presentembodiment, the central optical axis S1 is a normal line which passesthrough a center of a light-emitting surface of the light-emitting unit320. As shown in FIG. 4, in some embodiments, the light-emitting units320 are arrayed in a first direction D1 and a second direction D2. Inthe present embodiment, the light-emitting units 320 are arranged inrectangular arrays, and embodiments of the present disclosure are notlimited thereto. In other embodiments, the light-emitting units 320 mayalso be arranged in annular arrays, in circular arrays, or in otherarrangement manners.

Referring to FIG. 4 and FIG. 5, the packaging structures 330respectively cover and correspond to the light-emitting units 320. Eachof the packaging structures 330 has a central axis S2 which is verticalto the substrate 310. In the present embodiment, the packagingstructures 330 are arc-shaped structures. The central axis S2 of thepresent embodiment passes through the highest point of the arc-shapedstructure. As shown in FIG. 4, each of the light-emitting units 320 isshifted relative to its corresponding packaging structure 330. In otherwords, the light-emitting units 320 are respectively and correspondinglylocated in the packaging structures 330, and each of the light-emittingunits 320 is located near an edge of its corresponding packagingstructure 330. Therefore, the central optical axis S1 of each of thelight-emitting units 320 is offset from the central axis S2 of itscorresponding packaging structure 330 by a distance F1. In the presentembodiment, the central optical axes S1 of the light-emitting units 320are shifted in the same direction from the central axes S2 of thepackaging structures 330 by the same distance F1.

As shown in FIG. 4 and FIG. 5, in one embodiment, an included angle θ1is formed between the first direction D1 and a connecting line, in whichthe connecting line is located between the central optical axis S1 ofeach of the light-emitting units 320 and the central axis S2 of thepackaging structure 330 corresponding to each of light-emitting units320. The included angle θ1 is 45 degrees. As shown in FIG. 4, in oneembodiment, a first distance A1 is formed between the central opticalaxes S1 of any two adjacent light-emitting units 320, and a seconddistance A2 is formed between the central axes S2 of any two adjacentpackaging structures 330 which respectively cover the two adjacentlight-emitting units 320. The first distance A1 is equal to the seconddistance A2. In other words, the light-emitting units 320 and thepackaging structures 330 are arranged at an equal interval, so thatthere is no need to change the conventional LED manufacturing processand its dispensing process.

It is noted that, the light-emitting units 320 are shifted relative tothe packaging structures 330, so that the brightest position (i.e. aportion which is located at the central optical axis S1) of each of thelight-emitting units 320 and the highest position where the central axisS2 passes through of each of the packaging structures 330 are staggered.In other words, light emitted from the portion which is located at thecentral optical axis S1 of each of the light-emitting units 320 does notpass through the central axis S2 of each of the packaging structures.Therefore, referring to FIG. 6, FIG. 6 is a diagram of ray tracingsimulation of the light source structure in accordance with anembodiment of the present disclosure. When the light-emitting units 320are shifted from their corresponding packaging structures 330, theamount of light emitted from the side surfaces of the packagingstructures 330 is increased, so that the brightness of dark areaslocated between any two adjacent packaging structures 330 is alsoincreased.

Referring to FIG. 7A, FIG. 7A is a schematic diagram showing a lightsource structure in accordance with an embodiment of the presentdisclosure. It is noted that, the light source structure 300 in FIG. 7has substantially the same structure as the light source structure 300in FIG. 4. In order to clearly explain the optical principle of thepresent disclosure, different reference numerals are used in FIG. 7A torepresent substantially the same element, such as a light-emitting body320 a, a light-emitting body 320 x, a light-emitting body 320 y and alight-emitting body 320 z. As shown in FIG. 7A, the light sourcestructure 300 includes plural light-emitting bodies, such as thelight-emitting body 320 a, the light-emitting body 320 x, thelight-emitting body 320 y and the light-emitting body 320 z, arranged onthe substrate 310. The light-emitting unit 320 a is mainly constitutedby the light-emitting unit 320 and the packaging structure 330, andstructures of the light-emitting unit 320 x, the light-emitting unit 320y and the light-emitting unit 320 z are substantially the same as thelight-emitting unit 320 a. As shown in FIG. 7A, the light-emittingbodies are arranged along the first direction D1 and the seconddirection D2. With the light-emitting body 320 a as a reference, thelight-emitting bodies 320 x are located at two opposite sides (i.e. aleft side and right side of the light-emitting body 320 a as shown inFIG. 7A) of the light-emitting body 320 a along the first direction D1,and light-emitting bodies 320 y are located at two opposite sides (i.e.an upper side and a lower side as shown in FIG. 7A) along the seconddirection D2, and the light-emitting bodies 320 z are respectivelylocated at a upper right side, a lower right side, a upper left side anda lower left side of the light-emitting body 320 a. Under the conditionthat the light-emitting bodies are arranged along the first direction D1and the second direction D2 equidistantly, because a distance betweenthe light-emitting body 320 a and the light-emitting body 320 z which islocated oblique to the light-emitting body 320 a is greater than adistance between the light-emitting body 320 a and the light-emittingbody 320 x (or the light-emitting body 320 y), a relatively dark area islikely formed between the light-emitting body 320 a and thelight-emitting body 320 z. In order to compensate the light emitted fromthe central optical axes S1 of the light-emitting units 210 for the darkareas, the light-emitting units 320 of the present disclosure areshifted by a distance relative to the packaging structures 330 in thesame oblique direction. Therefore, the contrast between bright and darkareas of the light source structure 300 can be reduced, therebyobtaining a better light-mixing effect.

If the light-emitting units are merely moved relative to the packagingstructures in a horizontal direction or a vertical direction, the shapeand the dimension of the dark areas between any two adjacentlight-emitting bodies along the oblique direction are not changed much.If the light-emitting units which surround a central light-emitting bodyare moved relative to the central light-emitting body in a radialdirection, bright areas of the light-emitting bodies which surround thecentral light-emitting body are far away from a bright area of thecentral light-emitting body, thus resulting in an increase of dimensionof a dark area which surrounds the central light-emitting body, whicheffects the appearance and taste of the display device. Therefore, byshifting the light-emitting units in their corresponding light-emittingbodies along the same oblique direction, the dark areas between any twoadjacent light-emitting bodies which are arranged along the obliquedirection can be reduced, and light energy saved by reducing the darkareas can be transferred to other areas to increase the overallbrightness.

Referring to FIG. 3, FIG. 7A and FIG. 7B, FIG. 7B is a diagram oflight-mixing effect simulation of the light source structure inaccordance with an embodiment of the present disclosure. Compared withthe light mixing effect generated by the conventional light emittingdiodes, the light source structure 300 of the present embodiment has alower contrast between the bright and dark areas has a better the lightmixing effect. More specifically, as shown in FIG. 3, in the diagram oflight-mixing effect simulation generated by the conventional lightemitting diode, it can be seen that a dark dot in the center of eachlight-emitting body 110 a represents a light-emitting area with thehighest brightness of the light-emitting chip 110, and a light gray areawhich surrounds the center dark dot represents a light-emitting areawith a sub-brightness of the light-emitting chip 110, and a dark grayarea located between any two adjacent light-emitting bodies 110 arepresents the dark area R1 as described in the present disclosure. Asshown in FIG. 3, there is a large dark area which surrounds thelight-emitting body 110 a. Compared to FIG. 3, the simulation diagram ofthe light mixing effect generated by the light source structure 300 inFIG. 7B shows that, the areas in which the light-emitting units 320 arelocated have the highest brightness, although the brightness of thoseareas is slightly lower than the brightness of the area in which thelight-emitting chips 110 are located, the overall brightness of thebacklight module would not be affected. A size of a light-emitting areawith a sub-brightness which surrounds each of the light-emitting units320 is not changed too much. On the other hand, the dark gray areasshown in FIG. 7B have a lower color level than the dark gray areabetween any two adjacent light-emitting bodies 110 a in FIG. 3, meaningthat the overall light mixing effect of the light source structure 300shown in FIG. 7B is better. The reason is that the light sourcestructure 300 of the present disclosure can direct the light emittedfrom the light-emitting units 320 along the central optical axis S1 oralong the normal line of the substrate 310 to deviate from the centraloptical axis S1, and can guide a portion of the light in the brightareas to the dark areas, thereby resolving a problem of the contrastbetween the bright areas and the dark areas, thus improving the overalloptical taste of the backlight module. Therefore, by shifting thelight-emitting units 320 relative to their corresponding packagingstructures 330 can generate a better light mixing effect of the lightsource structure 300.

Referring to FIG. 8, FIG. 8 is a schematic diagram showing a displaydevice 500 in accordance with an embodiment of the present disclosure.The display device 500 of the present embodiment mainly includes abacklight module 400 and a display panel 510. The display panel 510 isdisposed in front of the backlight module 400. The backlight module 400includes the aforementioned light source structure 300 and at least oneoptical film 410 disposed above the light source structure 300.Referring to FIG. 4, the light light-emitting units 320 are arrayed onthe substrate 310, and the optical film 410 is able to be applied indirect-lit module to receive light emitted from the light sourcestructure 300. The optical film 410 is used to mix light generated fromthe light-emitting units 320 of the light source structure 300 so as toincrease the overall luminance of the backlight module 400. In thepresent embodiment, the optical film 410 includes a main body 411 andplural optical structures 412 disposed on the main body 411. Morespecifically, the main body 411 has a first optical surface 411 a and asecond optical surface 411 b opposite to the first optical surface 411a. In the present embodiment, the first optical surface 411 a facestowards the light source structure 300. The optical structures 412 aredisposed on the first optical surface 411 a and face toward the lightsource structure 300. The optical structures 412 are used to reflect andrefract light. The light source structure 300 of the present disclosurecan direct a portion of the light which is emitted from the center ofthe light-emitting units 320 diagonally outward, which helps to reducethe contrast between the bright and dark areas of the light sourcestructure 300. Compare the ray tracing situations of the light-emittingbody 110 a in FIG. 2 with the light-emitting body 320 a of the presentdisclosure in FIG. 6, light density emitted from the center of thelight-emitting body 320 a shown in FIG. 6 is lower than light densityemitted from the center of the light-emitting body 110 a shown in FIG.2, and light density emitted obliquely from the light-emitting body 320a shown in FIG. 6 is greater than light density emitted obliquely fromthe light-emitting body 110 a shown in FIG. 2. Therefore, a portion ofthe light emitted obliquely from the light-emitting body 320 a can bereflected back to the substrate 310 by the optical structures 412, andthe substrate 310 can further reflect the light back to the opticalstructures 412, so that the light which is not emitted out of theoptical film 410 can be efficiently recycled and reused, therebyreducing the loss of the light and evenly mixing the exiting light theoptical film 410.

Simultaneously referring to FIG. 8 and FIG. 9, FIG. 9 is a schematicstructural diagram showing an optical structure in accordance with anembodiment of the present disclosure. In one embodiment, each of theoptical structures 412 is a tapered structure and has plural sidesurfaces 412 a jointed together to form a vertex 413. Each of theoptical structures 412 has a central line L1 which is vertical to themain body 411 of the optical film 410. The vertex 413 is located on thecentral line L1, and the central line L1 is vertical to the firstoptical surface 411 a or the second optical surface 411 b of the mainbody 411. More specifically, as shown in FIG. 9, each of the sidesurfaces 412 a is a composite surface which is has two or more surfaceunits jointed together. In the present embodiment, each of the opticalstructures 412 is a quadrangular pyramid structure which has four sidesurfaces 412 a. Each of the side surfaces 412 a is a composite surfacewhich has a first layer surface unit 412 b and a second layer surfaceunit 412 c jointed along the central line L1. In the present embodiment,each of the first layer surface units 412 b has a normal line N1, andeach of the second layer surface units 412 c has a normal line N2. It isnoted that, the “normal lines” as referred herein, refer to linesrespectively perpendicular to the first layer surface units 412 b andthe second layer surface units 412 c. Extending directions of the normallines N1 and the normal lines N2 are different. As shown in FIG. 8, anincluded angle 82 is formed between the central line L1 and the normalline N1 of each of the first layer surface units 412 b, and an includedangle 83 is formed between the central line L1 and the normal line N2 ofeach of the second layer surface unit 412 c. The included angles 82which are respectively formed between the normal line N1 and the centralline L1 of each of the first layer surface unit 412 b are equal, and theincluded angles 83 which are respectively formed between the normal lineN2 and the central line L1 of each of the second layer surface unit 412c are equal, in which the included angles 82 are not equal to theincluded angles 83. In other words, the first layer surface unit 412 band the second layer surface unit 412 c are different inclined surfaceshaving different inclinations. In some embodiments, the included angles82 of the first layer surface units 412 b which are near the vertex 413can be designed to be greater or smaller than the included angles 83 ofthe second layer surface units 412 c which are away from the vertex 413,so as to from different inclined surfaces having different inclinations.Therefore, by using different inclined surfaces having different degreesof inclinations to refract and reflect light, the light generated byeach of the light-emitting units 320 can be scattered as wide aspossible to avoid light concentration at a specific angle or theemitting light concentrated upward, so that light can be emitted alongdifferent paths so as to achieve the objects of uniformizing light andincreasing light luminance. In addition, in the optical structure 412 ofthe present embodiment, the included angles 82 of the first layersurface units 412 b which are near the vertex 413 are smaller than theincluded angles 83 of the second layer surface unit 412 c which are awayfrom the vertex 413. In other words, the included angles between thenormal line and the central line of each of the surface units becomesmaller with increased distances between the respective surface unitsand the first optical surface. Therefore, the manufacturing process ofthe optical film 410 of the present disclosure is easy and has highyield.

It is noted that, in the embodiment of FIG. 8, the optical structures412 are disposed on the first optical surface 411 a of the main body411, which is not used to limit the present disclosure. In otherembodiments, the optical structures can be disposed on the secondoptical surface of the main body, or the optical structures can bedisposed on the first optical surface and the second optical surface ofthe main body at the same time, thereby achieving the same light mixingeffect.

In other embodiments, the optical structures may have different designs.Referring to FIG. 10, FIG. 10 is a schematic structural diagram showinganother optical structure 610 in accordance with an embodiment of thepresent disclosure. In the embodiment of FIG. 10, the optical structure610 has four side surfaces 612, and each of the side surfaces 612 is asingle surface, especially a plain surface. Referring to FIG. 11, FIG.11 is a schematic structural diagram showing another optical structure620 in accordance with an embodiment of the present disclosure. In theembodiment of FIG. 10, the optical structure 620 has four side surfaces612 a, and each of the side surfaces 612 a has three surface units 612b, 612 c, and 612 d jointed together. In the present disclosure, each ofthe optical structures is not limited to a quadrangular pyramidstructure. In other embodiments, each of the optical structures can be atriangular pyramid structure, a pentagonal pyramid structure, a conestructure, or other structures that can refract and reflect light toachieve the object of mixing light.

It is noted that, the optical structures described above are not limitedto be convex structures. In other embodiments, the optical structurescan be designed to be concave structures. Referring to FIG. 12, FIG. 12is a schematic structural diagram showing an optical film 700 inaccordance with another embodiment of the present disclosure. Theoptical film 700 of the present embodiment includes a main body 710 andplural optical structures 720. The main body 710 has a first opticalsurface 711 and a second optical surface 712 opposite to the firstoptical surface 711, and the optical structures 720 are disposed on boththe first optical surface 711 and the second optical surface 712. In thepresent embodiment, the optical structures 720 are concave structures.Each of the optical structures 720 is a tapered structure and has pluralside surfaces and a vertex. Therefore, when the light passes through theoptical film 700, the light can be refracted by the side surfaces ofthese tapered structures to travel along different path directions,thereby achieving the objects of uniformizing light and enhancinglight-emitting luminance. It is noted that, the structural design ofoptical structures 720 is similar to the aforementioned opticalstructures 412, 610 or 620, and the optical structures 720 also can beapplied to the aforementioned backlight module and display device, andthe application principles of the optical structures 720 are the similarto those of the aforementioned embodiments, and therefore will not bedescribed again herein.

It should be noted that, each of the optical structures of the presentdisclosure has plural side surfaces to refract multi-directional lightemitted from the light source structure, thereby changing the directionof light path, so as to avoid the problem of high intensity of lightemitted from directly above each packaging structure and weak intensityof light emitted from two sides of each packaging structure. In otherwords, each of the optical structures of the present disclosure does nothave a surface which is parallel to the light emitting surface of thelight source structure. For example, as shown in FIG. 9 and FIG. 0.12,the side surfaces of each of the optical structures which are connectedto form a vertex and are not parallel to the light emitting surface ofthe light source structure. Therefore, after the light is emitted fromthe light source structure, traveling directions of most of the lightcan be changed by the side surfaces of the optical structures.Therefore, the present disclosure not only can reduce the contrastbetween the bright areas and the dark areas to achieve good light-mixingeffect and better optical taste, but also can increase light uniformityand enhance light luminance.

Moreover, as shown in FIG. 10, the optical structure 610 in FIG. 10 hasfour side surfaces 612, and each of the side surfaces 612 is a singlesurface. Therefore, most of the light generated by the light sourcestructure can be diverted by the side surfaces 612 of the opticalstructure 610 to travel along four directions, and will no longer beconcentrated directly above the packaging structures, so that the lightuniformity can be improved. With the increase in the numbers of the sidesurfaces of each optical structure, the light can be diverted to travelalong more directions. However, due to the increase in the number oftraveling directions, the overall light energy remains unchanged, whichmay result in the reduction of the light energy in each direction.Therefore, each of the side surfaces can be designed by jointing two ormore than two layers of surface units together so as to change therefraction and reflection directions of a portion of the light.

For example, simultaneously referring to FIG. 10 and FIG. 13, FIG. 13 isa diagram of light-mixing effect simulation of the optical structureshown in FIG. 10. In the embodiment of FIG. 10, the four side surfaces612 of the optical structure 610 are designed to deflect light towardfour primary directions. For example, as shown in FIG. 13, a mainportion of light is guided to four primary directions, such as 30° to60°, 120° to 150°, 210° to 240°, and 300° to 330°. Simultaneouslyreferring to FIG. 9 and FIG. 14, FIG. 14 is a diagram of light-mixingeffect simulation of the optical structure shown in FIG. 9. In theembodiment of FIG. 9, the four side surfaces 412 a of the opticalstructure 412 can also deflect light toward the four primary directions,and because each of the side surfaces 412 a in FIG. 9 has the firstlayer surface unit 412 b and the second layer surface unit 412 c, thelight emits towards the first layer surface unit 412 b and second layersurface unit 412 c can be refracted and reflected towards differentdirections. By the design of the first layer surface unit 412 b and thesecond layer surface unit 412 c, a portion of the light which travelsalong four primary directions can be diverted to travel along other foursub directions which are slightly offset from the four primarydirections. As shown in FIG. 14, intensities of light guided to fourprimary directions, such as 30° to 60°, 120° to 150°, 210° to 240° and300° to 330° are lower than intensities of the light shown in FIG. 13,which means that the light is not only guided to the four primarydirections, but also to the other four sub directions. Therefore, thelight intensities in the four primary directions are slightly reduced,and the overall light luminance becomes uniform. In other words, thedesign of the first layer surface unit 412 b and the second layersurface unit 412 c can increase the number of light traveling directionswithout significantly affecting the light energy of the four primarydirections, thereby improving the light uniformity and maintaining thelight energy of the primary directions. It is noted that, theaforementioned optical film is able to be applied in the direct-litbacklight module to receive light emitted from the light sourcestructure, and divert the light to the primary directions, so as toreduce the accumulation of the light. Besides, the at least two layersof the surface units of each optical structure facilitates to divert aportion of the light from the primary directions to the sub directions.Therefore, the light-accumulation reducing effect is more enhanced andthe objects of uniformizing light and improving the light luminance areachieved. In addition, the optical film of the present disclosure whichis used to be applied in the direct-lit backlight module has differentfunctions from a conventional optical film which is used to be appliedin a side-lit backlight module. Because a light source of the side-litbacklight module is set at a side of a light guide plate, light emittedfrom the light source and entering the light guide plate will beobliquely emitted out from a light-emitting surface of the light guideplate, so as to form an included angle between a light-emittingdirection and the normal line of the light-emitting surface of the lightguide plate. For the oblique light-emitting direction, the function ofthe conventional optical film applied to the side-lit backlight moduleis to guide the oblique light-emitting direction into a normaldirection, for example, a turning film with lenticular microstructureswill be applied. Compared to the function of the conventional opticalfilm, the function of the optical film of the present disclosure is toguide the lights to several primary directions or sub directions.Therefore, the functions between the conventional optical film and theoptical film of the present disclosure are different.

It is noted that, in the embodiment of the display device 500 as shownin FIG. 8, the optical film 410 is collocated with the light sourcestructure 300 which has the light-emitting units 320 disposed offsetfrom the packaging structures 330. In other embodiments, the opticalfilm 410 can be collocated with different light source structure.Referring to FIG. 15, FIG. 15 is a schematic diagram showing a displaydevice 800 in accordance with an embodiment of the present disclosure.The display device 800 mainly includes a light source structure 900, theaforementioned optical film 410 and a display panel 810. The lightsource structure 900 includes a substrate 910 and plural light-emittingunits 920 arrayed on the substrate 910. Therefore, after light emittedby the light-emitting units 920 passes through the optical film 410, thelight can dispersedly emit out from the optical film 410, therebyincreasing light informality. In the present embodiment, the opticalfilm 410 can also be replaced with the optical film 700 as shown in FIG.12 to achieve the same optical effect.

According to the aforementioned embodiments of the present disclosure,by shifting the light-emitting units relative to the packagingstructures, the amount of the light emitted from the side surfaces ofthe packaging structures can be increased, thereby increasing thebrightness of the dark areas between any two adjacent packagingstructures and reducing the contrast between the bright and dark areasof the light source structure, so as to achieve a good light mixingeffect. On the other hand, the optical film of the present disclosurewhich has special optical structures can be cooperated with the lightsource structure of the present disclosure, so that light can bediverted to travel along different directions when passing through theoptical structures, thereby achieving the objects of uniformizing lightand improving the light luminance.

Although the present disclosure has been described in considerabledetail with reference to certain embodiments thereof, other embodimentsare possible. Therefore, the spirit and scope of the appended claimsshould not be limited to the description of the embodiments containedherein.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentdisclosure without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present disclosurecover modifications and variations of this invention provided they fallwithin the scope of the following claims.

What is claimed is:
 1. A backlight module, comprising: a light sourcestructure configured to emit light; and at least one optical filmdisposed above the light source structure, wherein the optical filmcomprises: a main body; and a plurality of optical structures disposedon the main body, wherein each of the optical structures is a taperedstructure; wherein each of the optical structures has a plurality ofside surfaces, and a portion of light emitted from the light sourcestructure is guided toward a plurality of primary directions by the sidesurfaces of the optical structures, and therefore the light emitted fromthe light source is no longer concentrated on the top of each of theoptical structures.
 2. The backlight module of claim 1, wherein each ofthe optical structures faces towards the light source structure; and thelight source structure comprises a substrate and a plurality oflight-emitting units arrayed in a first direction and a second directionon the substrate, wherein each of the light-emitting units has a centraloptical axis which is vertical to the substrate.
 3. The backlight moduleof claim 1, wherein the main body has a first optical surface and asecond optical surface opposite to each other; each of the opticalstructures has a vertex and a central line, wherein the central line isvertical to the first optical surface or the second optical surface ofthe main body, and the vertex is located on the central line.
 4. Thebacklight module of claim 1, wherein each of the side surfaces is asingle surface; each of the side surfaces has a normal line, andextending directions of the normal lines are different; and includedangles between each of the normal lines and each of the central linesare equal.
 5. The backlight module of claim 1, wherein each of the sidesurfaces is a composite surface which is constituted by two or more thantwo surface units jointed in an extending direction of the central line.6. The backlight module of claim 1, wherein the side surfaces of each ofthe optical structures surround the central line, and each of the sidesurfaces is a composite surface which is constituted by two or morelayers of surface units jointed in an extending direction of the centralline; each of the surface units has a normal line; a plurality ofincluded angles are formed between the central line and the normal linesof the surface units, wherein the included angles between the centralline and the normal lines of the surface units which are located in thesame layer and surround the central line are substantially the same; andthe included angles between the central line and the normal lines of thesurface units which are located in different layers and surround thecentral line are different; and a first portion of light emitted fromthe light source structure is diverted along a plurality of primarydirections, and the first portion of light is diverted by the sidesurfaces of the optical structures which are near the vertex; and asecond portion of light emitted from the light source structure isdiverted along a plurality of sub directions which are different fromthe primary directions, and the second portion of light is diverted bythe side surfaces of the optical structures which are away the vertex,wherein the light emitted from the light source structure is guided todifferent travel paths instead of being concentrated on the top of eachof the light source structures.
 7. The backlight module of claim 6,wherein the included angles between the central line and the normallines of the surface units which are located near to the vertex aresmaller than the included angles between the central line and the normallines of the surface units which are located away from the vertex. 8.The backlight module of claim 6, wherein the included angles becomesmaller with increased distances between the respective surface unitsand the first optical surface.
 9. The backlight module of claim 1,wherein the main body has a first optical surface and a second opticalsurface opposite to each other; and each of the optical structures is aconvex structure protruding from the first optical surface and/or thesecond optical surface.
 10. The backlight module of claim 1, wherein themain body has a first optical surface and a second optical surfaceopposite to each other; and each of the optical structures is a concavestructure which is recessed into the first optical surface and/or thesecond optical surface.
 11. The backlight module of claim 1, wherein thelight source structure comprises: a substrate; a plurality oflight-emitting units arrayed in a first direction and a second directionon the substrate, wherein each of the light-emitting units has a centraloptical axis which is vertical to the substrate; and a plurality ofpackaging structures respectively covering and corresponding to thelight-emitting units, wherein each of the packaging structures has acentral axis which is vertical to the substrate; wherein the centraloptical axes of the light-emitting units are shifted in the samedirection from the central axes of the packaging structures; wherein anincluded angle is formed between a connecting line and the firstdirection or the second direction, and the connecting line is locatedbetween the central optical axis of each of the light-emitting units andthe central axis of the packaging structure corresponding to the each oflight-emitting units.
 12. The backlight module of claim 11, wherein theincluded angle is 45 degrees.
 13. The backlight module of claim 11,wherein a first distance is formed between the central optical axes ofany two adjacent light-emitting units; and a second distance is formedbetween the central axes of any two adjacent packaging structures;wherein the first distance is equal to the second distance.
 14. Thebacklight module of claim 11, wherein an offset distance is formedbetween the central optical axis of each of the light-emitting units andthe central axis of the packaging structure corresponding to the each ofthe light-emitting units, and the offset distances are equal.
 15. Adisplay device, comprising: a backlight module of claim 1; and a displaypanel disposed in front of the backlight module.
 16. A display device,comprising: a backlight module of claim 11; and a display panel disposedin front of the backlight module.